This invention relates generally to a pneumatic (compressed-air-operated) reciprocating motor, and more particularly to pumping apparatus incorporating the motor for pumping a fluid.
In one embodiment, the invention involves an air operated liquid pump of the type disclosed in U.S. Pat. No. 5,924,602, issued Jul. 20, 1999, entitled Air Operated Liquid Pump. In another embodiment, the invention involves a grease gun of the type disclosed in the co-assigned U.S. Pat. No. 5,779,105, issued Jul. 14, 1998, entitled Air Operated Grease Gun (“the '105 patent”), having been developed as an improvement on the commercial version of the gun disclosed in the '105 patent. While the liquid pump and grease gun disclosed in these patents have been generally satisfactory, they are subject to breakage and shortened life, necessitating early repair. Further, the plunger of the motor has a tendency to jam on occasion.